The main objective of the research is to develop and to better understand a behavioral procedure for the treatment of essential hypertension. Patients will be evaluated by a battery of medical, psychometric, and psychophysiological procedures at regular intervals and have multiple, daily blood pressure determinations. The effects of behavioral procedures on these variables will be measured. The behavior therapy procedure ("Metronome- Conditioned Relaxation") to be evaluated entails the use of miniaturized electronic metronomes. The experimental group has a standardized longitudinal sequence of daily measurements (Baseline Period "A") and treatments (Metronome- Conditioned Relaxation, "B") in an A-B-A-B-A design. A comparison group will be studied in a similar sequence but with "B" entailing the performance of a minimally relaxing task (mild paced exercises). The psychometric and psychophysiological assessment will be used to describe those patients with essential hypertension who are in our samples. These analyses will be inspected for purposes of understanding the ways in which the behavioral techniques achieve their effects on blood pressure.